Sand blasting apparatus



Aug. 17, 1937. H. WlLLSHAW SAND BLASTING APPARATUS Filed Feb. 10, 1957 4Sheets-Sheet 1 17, 1937. H. WILLSHAW 2,090,278

SAND BLASTING APPARATUS Filed Feb. 10, 1937 4 Sheets-Sheet?llIIllIIIIEIIIIIIIIIIIIIHIIHIlllllllllllllllllllll lll g- 1937- H.WlLLSHAW 2,090,278

SAND BLASTING APPARATUS Filed Feb. 10, 1937 4 Sheets-Sheet 5 i n I 5 i IFiled Feb. 10, 1937 4 Sheets-Sheet 4 Patented Aug. 17, 1937 UNITEDSTATES z,09c,27s

PATENT QFFHCE SAND BLASTING APPARATUS Application February 10, 1937,Serial No. 125,047 In Great Britain November 27, 1935 6 Claims.

My invention relates to apparatus for blasting articles, particularlyhollow annular articles, such as tire molds with sand or other material.

In sand blasting hollow articles, such as tire 5 molds, the blastingmaterial tends to collect in the contours of the mold, particularly ifthe latter is disposed horizontally. Consequently, the blast, instead ofimpinging onto the surface to be blasted may impinge to a large extentupon 10 the sand or other material, which accordingly tends to obstructand impair the efiectiveness of the sandblast.

This tendency is overcome in my present invention, in which the articleto be blasted is rotated in such a manner relative to the blastingnozzles, as to cause the sand to fall freely from the surface beingblasted and leave the latter freely and unobstructedly exposed to theblast. Preferably, the blasting takes place in a blastin chamber intowhich the mold or other article to be blasted is conveyed to operativeposition and then rotated while subjected to the blast.

Any suitable means may be employed for con veying the mold, preferablythe mold is rotatably mounted on a carriage, which may be slid orcarried or rolled to the blasting position, whereupon it may be rotatedas a unit together with the mold, or the mold may be rotated on thecarriage by a suitable supporting shaft .and clutch arrangement. Forexample, in a preferred construction, the carriage and mold mounted onit are rolled into the blasting chamber between pairs of guide rails,until it comes to a position on a pair of driving rolls or gears. Therotation of the latter causes the carriage and the mold carried by it tospin with the axis of the mold in approximately the position of the axisof rotation. This rotation brings the material surfaces of the moldabove and free of any deposits of sand and in position to receive theunobstructed sand blasts. The driving mechanism may be so arrangedeither that the carriage automatically comes into engagement with thedriving rollers or gears as it reaches operative position, or it may beclutched through a spindle,

particularly if it is pushed or conveyed into the chamber by an overheadconveyor or by such mechanism as a pantin roller type of conveyor.

Various features of the invention are illustrated by way of example inthe accompanying drawings, in which- Figs. 1 and 2 are diagrammaticfront and end elevations respectively, parts being broken away -55 toshow interior constructions, of a preferred form of the invention, atire mold being shown in full lines in Fig. 2 and indicated in dot anddash lines in Fig. l, and Figs. 3 to 8 are diagrammatic elevations ofvarious modifications or alternative constructions of the invention, thetire molds or other hollow articles being indicated in dot and dashlines in Figs. 2 to '7 and in full lines in Fig. 8.

Apparatus according to the embodiment of the invention illustrated inFigs. 1 and 2 comprises a blasting chamber ll containing blasting meanspreferably comprising a pair of oscillating blast nozzles l2, and asuitable take-away l3 for the used blasting material.

The front and the two ends of this chamber are provided with doors-avertically sliding door M .at the front for inspection purposes andhinged doors I 5 and it at the ends to permit ingress and egress of themolds l1.

Passing through said doors l5 and 16 into and out of the chamber are tworails is and I9, one above the other, on which the carriage aforesaid isadapted to run, said carriage, 26, being disposed vertically betweensaid rails and rotating on a horizontal axis as it rolls therealong.

It is convenient to use two carriages so that when the one 20 is in usein the chamber another 2| is available for loading.

In its preferred form the carriage is of annular construction andcomprises (a) a. part having guiding coaction with said rails, (13) apart having rolling coaction therewith, (c) a part which providesanchorage for the mold, and (d) a part having driving coaction withdriving means inside the chamber.

As shown in Figures 1 and 2, part (a) comprises a. pair of annularflanges 22 which embrace the sides of the rails, part (b) comprises acylindrical structure 23 which rolls on the lower rail, while part (0)comprises a central structure 24, made conical to seat a range ofdifferent size molds, upon which the mold is anchored by a clamp plateand central screw 25: and part (d) is provided by part (b) having gearteeth 26.

Said teeth actually roll on the surface of the lower rail during thetransportation phases of the operation and are complementary to teeth ona driven gear wheel Z'l disposed in the blasting chamber for the purposeof rotating the carriage 2c, spaced laterally from this gear wheel is afurther wheel 23 which acts as a bearing wheel for the carriage duringthe driving phase of the operation.

As shown in Fig. 1 these wheels 21 and 28 break into the lower rail l9which is thus in two parts (i) and (ii) extending to and from saidwheels, so that when the carriage is rolled along said rails its teeth26 will automatically register with the gear 21 when they roll over andinto alignment therewith.

Means are preferably provided to lift the carriage out of engagementwith the Wheels 21 and 28 when blasting is over, so as to ease the dif-10 ficulty of getting said carriage loaded with the heavy mold, onto thetake-away rail. These means may comprise mechanical power magnifyingmeans, such as systems of levers, or as shown in Figs. 1 and 2, maycomprise a fluidpressure operated plunger 29 adapted to contact a partof the mold or carriage to effect said lifting, thereby to make saidcarriage free to be rolled onto the rail along which it is transportedout of the chamber.

The preferred manner of operating this particular embodiment of myinvention is as follows:-

Assume that a given tire mold is being treated, one carriage, 23, beingengaged in operating in the chamber, and assume that another carriage,2|, is empty on the left-hand rail outside the chamber as shown in Fig.1.

While the treatment of the one mold proceeds, another mold is brought,by overhead hoist or other means, to the empty carriage 2|, is placedthereon, and is fastened thereto by the clamp plate and attaching meanssuch as a bayonet type joint or central screw 25. When the mold beingtreated is finished, the end doors are opened, the piston 29 is operatedto lift said mold off the wheels 21 and 28, and the carriage is thenrolled onto the right-hand rail (1') and therealong out of the chamber.

The support 2| carrying the other mold to 40 be cleaned is then rolledalong the left-hand rail (ii) into the chamber, the gear teeth 26rolling into driving engagement with the gear wheel 21, and intosupporting coaction with the bearing wheel 28.

The end doors are then shut and blasting is carried out. The treatedmold is then removed from its support leaving the same empty for theabove sequence to be repeated as desired, next time from right to left,then from left to 50 right, and so on.

It should be understood that I do not confine myself to the aboveembodiment of my invention, the following alternatives, modifications oradditions being given by way of example.

Additional mold-guiding, aligning or supporting means may be providedparticularly inside the chamber, said means comprising for examplerollers 30 against Which the mold or the carriage may bear duringrotation.

The invention is of 1 course preferably used in association with theusual adjuncts common to sandblast plant such for example as oscillatingblasting nozzles and means for reclaiming the blasting material throughfilters or the like.

5 Means may be provided to adjust the nozzles so that they play on themold in the most efficient manner, both as to angle, alignment, speedand/or path of oscillation.

As shown in Figs. 1 and 2 each nozzle mecha- 70 nism convenientlycomprises three bars 3|, 32 and 33. In use bars 32 and 33 are fixed o-nbar 3| which oscillates, to traverse the nozzle to and fro across themold, by means of the crank mechanism 34. For adjustment purposes, by

75 manipulating the bars 32 and 33 in relation to each other and the bar3|, various positions of the nozzle can be readily arrived at.

The preferred form of drive as shown comprises a motor 35 which drivesVia chain gearing 36 a shaft 31 which drives the gear 21 directly andthe crank mechanism 34 via further chain gearing 38.

Instead of rotating the mold as illustrated I may use a suitable clutcharrangement comprising, as shown for example in Fig. 3, a part 39 fixedto the carriage, and a driven part 40, adapted to be operativelycoupledtogether by a sliding part 4|.

This coupling may be either a positive drive or a friction or othersuitable drive, as for example suitably disposed cones or the like; inthe circumstances however positive gearing is preferred.

Instead of the carriage itself engaging driving means, said carriage maybe provided primarily for transporting the mold into and out of thechamber and supporting it therein, drive being actually applied to themold itself rather than to the carriage, as shown for example at 42 inFig. 4, this being applicable in instances where there is a periphery ofthe mold which is sufliciently truly circular.

Instead of complete rotation we may use rotational oscillation for themold.

As to the means for transporting the mold into and out of the chamber,it should be understood that this does not necessarily comprise rails asdescribed, for example said transporting means may be some other form ofconveyor, as for example of the pantin roller type along which the moldwould be slid.

Or, as shown for example in Fig. 5, the mold may be carried upon awheeled truck 43 adapted to run on rails or a suitable guideway 44, saidmold for example being carried upon a spindle 45 associated with aclutch similar to that shown I carried by a sling 48 pendant from thechain 41,

the latter being supported in runners 49; the clutch mechanism may bethe same as before.

The mold may be moved into and out of blasting position by any suitablemeans, as for example by simple hand manipulation--rails where used maybe inclined or tiltable--or I may provide suitable haulage or mechanicaltransporting or assisting gear comprising, for example, a lever or thelike to magnify the hand effort of rolling.

Alternatively, as shown in Fig. 'l in application to the arrangementaccording to Figs. 1 and 2, I may use a chain 50 preferably power drivenand adapted to progress the molds along the rails l8 and I9, said chainas shown coacting with a bearing 5| at the centre of the cone 24 toallow the carriage to rotate.

A chain, such as this, may be the sole or main conveying or transportingmeans, the rails, for example, merely taking the weight.

And finally it should be understood that I do not necessarily use aseparate carriage as aforesaid. For example, the mold itself or a partthereon may coact with suitable transportation means, which take saidmold into and out of the chamber, and with suitable driving means, whichrotate said mold inside said chamber.

For example, as shown in Fig. 8, I may roll the mold itself alongchannels 52, 53 and rotate it by driving means 54 inside the chamber.

Having now particularly described my invention, I claim 1. Means forblasting hollow annular articles with sand or the like which comprises ablasting chamber, a blasting nozzle in said chamber, upper and lowerguiding and supporting rails leading toward said nozzles in saidchamber, a carriage having means to hold an article to be blasted withits axis horizontal and approximating the axis of said carriage, saidcarriage having a circular part to roll on and be guided by said railsmoving toward said nozzles and means near said nozzles to support androtate said carriage about its horizontal axis.

2. Apparatus for blasting hollow annular articles such as tire moldswith sand or the like which comprises a blasting nozzle, a runway, acarriage rolling on and guided in said runway to a position near saidnozzle, rotating driving and supporting wheels to support said carriagefor rotation in front of said nozzles and means for lifting saidcarriage from said supporting wheels back to said runway.

3. Apparatus for blasting hollow annular articles such as tire moldswith sand or the like which comprises a blasting nozzle, conveying meanscomprising a carriage on which said article is mounted, guide railssupporting said carriage and on which said carriage rolls to and from ablasting position relative to said nozzle and a pair of wheels forsupporting and rotating said carriage on an axis approximating the axisof said hollow article when in blasting position relative to saidnozzle.

4. Apparatus for blasting hollow annular articles such as tire moldswith sand or the like which comprises a blasting nozzle, conveying meansfor conveying articles to be blasted to and from a stationary blastingposition relative to said nozzle and comprising a carriage movable toand from blasting position, a spindle on said carriage to support thearticle to be blasted and means to rotate said spindle while in fixedstationary blasting position relative to said nozzle.

5. Apparatus for blasting hollow annular articles such as tire moldswith sand or the like which comprises a blasting nozzle, means forconveying a carriage to blasting position relative to said nozzle and torotate it with its interior in blasting position relative to saidnozzle, said means comprising a carriage having external gear teeth,rails to guide and support said carriage to and from its position ofrotation and a spur gear to engage the teeth of said carriage to drivethe latter when in blasting position.

6. Apparatus for blasting hollow annular articles such as tire moldswith sand or the like which comprises a blasting nozzle, means forrotating said article on its horizontal axis with its interior inoperative relation to said nozzle, a

runway, a carriage for said article rolling on and guided in said runwayto a blasting position and rotating driving and supporting wheels torotate said carriage in blasting position.

HARRY WILLSHAW.

